Add date value of

src/js.rs

@@ -372,6 +372,19 @@ extern {
     pub fn value_of(this: &Number) -> Number;
 }
 
+// Date.
+#[wasm_bindgen]
+extern {
+    pub type Date;
+
+    /// The valueOf() method  returns the primitive value of
+    /// a Date object.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/valueOf
+    #[wasm_bindgen(method, js_name = valueOf)]
+    pub fn value_of(this: &Date) -> Date;
+}
+
 // Object.
 #[wasm_bindgen]
 extern {

tests/all/js_globals/Date.rs

@@ -0,0 +1,30 @@
+#![allow(non_snake_case)]
+
+use super::project;
+
+#[test]
+fn value_of() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(proc_macro, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js::Date;
+
+            #[wasm_bindgen]
+            pub fn js_value_of(this: &Date) -> Date {
+                this.value_of()
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let date = new Date(Date.UTC(96, 1, 2, 3, 4, 5));
+                assert.equal(wasm.js_value_of(date), 823230245000);
+            }
+        "#)
+        .test()
+}

tests/all/js_globals/mod.rs

@@ -9,6 +9,7 @@ mod JsFunction;
 mod JsString;
 mod Number;
 mod Math;
+mod Date;
 
 #[test]
 #[cfg(feature = "std")]